Sweeney told the Times he would be submitting a one-sentence letter of resignation to the board at its end-of-year meeting today.

“It’s very hard to walk away from something … But I don’t think it would be right for me to be on the ballot in two places,” Sweeney told the paper for a story in today’s edition.

Sweeney’s freehold term expires at the end of 2011. If he had chosen to run for reelection, he would have been on the ballot for both a freeholder seat and his Senate seat. In the 2010 elections, two Republicans won seats on the Gloucester County freeholder board.

The Senate president had repeatedly said he was planning to resign as freeholder.